Field of the Invention
Various embodiments of the present invention relate to an automatic transmission for a vehicle, and particularly, to a multi-stages automatic transmission for the vehicle equipped with a gear train capable of implementing 11 forward-speeds and 1 reverse-speed and driving at an optimum point of the engine by multi-stages effect of a transmission.
Description of Related Art
Recently, the technology development need for performance improvement has emerged also similarly in the power train field by being more required need for fuel efficiency improvement due to strengthen of environmental regulations or rising oil prices.
As an appropriate power train technology corresponding to the need, there are an engine downsizing technology and a multi-staging technology of an automatic transmission. The engine downsizing has merits to reduce weight and improve fuel efficiency, and particularly, the automatic transmission multi-staging has merits of securing drivability and competitiveness of fuel efficiency at the same time by available design of an excellent gear ratio in terms of power performance and fuel efficiency by using many shift stages compared to 4-speed (or 5-speed), reverse 1-speed automatic transmission.
However, an automatic transmission is the way in which the more a shift stage is increased the more the number of internal components that make up the automatic transmission is increased by implementing the shift stage with a gear train applied a planetary gear set.
Thus, in the multi-staging of the automatic transmission, above all it is important to achieve drivability and fuel efficiency competitiveness with the gear train structure without increasing the number of internal components rather worsening vehicle mount ability, cost, weight and power transmission efficiency.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.